The DOT support in yEd Live is quite limited. It mostly supports the general graph structure and some very simple styling options.
This error usually indicates the usage of a certain GraphViz feature that cannot be parsed by yEd Live.
Please try to reduce your DOT file to the point where it can be loaded (e.g. remove any legend, advanced styling etc.), then add additional features to see what doesn't work.
If your file doesn't contain any confidential or personal data, you could also post it here and I'll have a look at what the problem may be.